Relative Afferent Pupillary Defect (hereinafter “RAPD”) also known as Marcus-Gunn pupil, is a condition in which pupils respond differently to light stimuli shone in one eye at a time due to unilateral or asymmetrical disease of the retina or optic nerve. Swinging flashlight test or Marcus Gunn test is one of the most basic eye exams that may be used for evaluating RAPD.
Swinging flashlight test may be performed in a dimly-lit room, using a strong light source. Pupillary reactions are observed as the light shines in one eye. Normally, when either eye is exposed to direct light, both eyes will constrict. In an individual with RAPD, shining light into an unaffected eye will cause both pupils to constrict, while shining light into the affected eye will yield a diminished constrictive response in both eyes. There may be drawbacks associated with this test. The major drawback may be the subjectivity of the examiner's opinion about the variations of pupil size and speed of response to light, which are important parameters in evaluating the state of RAPD. Also, the unsymmetrical test situation for either eye, may make the test procedure unreliable for mild RAPDs. Although the response of each eye to light stimuli should be measured independently and in isolation, the ability of swinging flashlight test in providing this condition is limited because both patient's eyes should be open to let the examiner check each pupil size change. Moreover, the ambient light in the room may affect the amount of light received by each eye, which may make the results prone to error.
Brightness Saturation Test (hereinafter “BST”) may be used along with swinging flashlight test to quantify RAPD. This method involves placing a series of neutral density filters in front of the intact eye to change the light intensity, and to repeat the swinging flashlight test. More particularly, this method is performed by increasing the density of the filters in front of the intact eye until the constriction of the defective eye is observed to be the same level as its impaired direct reflex.
Color Discrimination Test (hereinafter “CDT”) may be used along with swinging flashlight test and BST to quantify RAPD. This method involves placing a red object in front of one eye and asking the patient to choose the most similar color to the object from the color bar in front of the other eye. The amount of discrepancy among the two reds, results in quantification of RAPD. Similarly, due to the subjective and verbal communication between patient and doctor, determination of exact amount of difference between perceived values of the red object by each eye may not be quite possible.
A significant percentage of the human population is affected by Color Blindness. A patient suffering from color blindness may be unable or with limited ability to see color, or distinguish between colors under normal lighting conditions. Screening and more detailed quantitative tests may be developed to detect a color vision deficiency and determine the type and severity of color blindness.
Ishihara color vision test may be considered the most widely used color blindness test. In this test, the patient should be in a room with normal daylight. The examiner asks the patient to find and read a random number in a page which is covered with many dots of various colors, brightness and sizes. The complete test may involve checking 38 different images each on a separate page. Unlike people with normal vision, color blind patients are not able to find a number at all or they see a different number. Although it is one of the most common color blindness detection tests, however, it cannot be used for checking the vision of young children, because they cannot recognize different numbers and correct communication with them may not always be possible.
Farnsworth-Munsell 100 Hue Test is another popular test which makes quantification of color blindness possible. A patient should sort 400 small colored disks in a special order and the results will be compared to the standard known set. The difference between patient's results and the standard set determines the amount of color blindness. Other than the long time needed to perform this test which makes patients tired, the ambient light may affect the patient's perception of colors and may make the results prone to errors.
Problems such as human errors in measuring pupil size using naked eye; variations in testing conditions, such as changes in ambient light; uncontrollable and unintentional changes in penlight intensity due the variations in battery charges and etc., result in a long sought but unfulfilled need in the art for systems and methods that automatically assess and quantify ophthalmologic biomarkers of Marcus-Gunn and color blindness.
Moreover, after performing certain eye surgeries, patients may need to be monitored regularly with short intervals. Limited access to ophthalmologist due to busy appointments may impose a challenge on getting the high standard health service that patients deserve. Also, patients who live in remote areas have very limited access to specialists and cannot be routinely checked up.
Accordingly, there is a need in the art for a system and method that enables the patients to test their eyes at home and share the test results with their doctors, via for example an online method. This may speed up the time that doctors need to monitor their patients and check their bio-markers remotely and it may also increase the accuracy of the tests. There is further a need in the art for systems and methods that provide digital archiving of the test results, which let the doctors track the progression of patients' diseases or treatments over time.